Circuit breaker



Oc 9, 1957 P. M. CHRISTENSEN ETAL 2,311,505

cmcurr BREAKER Filed Dec. 11', 1955 ATTORNEYS United States PatentCIRCUIT BREAKER Paul M. Christensen, West Orange, and Dominik Wiktor,Newark, N. J., assignors to Federal EiiZC i ziQ Products Company,Newark, N. J., a corporation of Delaware Application December 11, 1953,Serial No. 397,662

22 Claims. (Cl. 200116) The present invention relates generally tomanually operated switches or circuit breakers and in particular toautomatic circuit breakers.

In manually closing a circuit breaker or a switch, the closing operationto effect the engagement of the contacts should be smooth, even andpositive. Persons who are inexperienced or timid in the operation ofcircuit making and breaking devices often have a tendency to close thedevice with hesitation and timidity when engaging the contacts forestablishing or making the electric circuit. Hesitancy or pausing justbefore the contacts are closed, generally known in the art as teasing,may permit the current to are across the gap between the contacts.Current flow across the high resistance of the gap may producesuflicient heat at the contacts to weld or fuse them together on theengagement thereof. In the case of automatically operated circuitbreakers, the fusing or sticking of the contacts prevents the automaticopening thereof upon overload and, therefore, removes the desired safetycontrol or tripping action from the circuit.

In view of the foregoing, an object of the present invention is theprovision of means for assuring a consistent and quick closing actionfor effecting the engagement of the contacts of manually operatedswitches and circuit breakers, regardless of hesitancy or uneven manualoperation by the operator.

Another object is to provide a quick make circuit breaker which ishandle free during the closing operation thereof to close the contactsthereof.

Another object is to provide for a positive off or opening operation ofa circuit breaker on manual opera-,

tion thereof to open the breaker whereby to effect opening of thebreaker manually in case the contacts stick or are welded to each otherand to provide added protection in the event that the main spring of thecircuit breaker breaks or is defective.

Another object is the provision in an automatic circuit breaker of meansfor providing an extra sharp blow to the mechanism thereof in order toopen the contacts, especially in the event that the contacts sticktogether or have a light or superficial weld to each other.

A further object is the provision of means to assist in the acceleratedopening of the contacts of a circuit breaker upon automatic operationthereof and also on manual operation where the handle is not held inposition.

The above and other objects, features and advantages of the presentinvention will be more fully understood from the following descriptionconsidered in connection with the accompanying illustrative drawings.

In the drawings which illustrate the best mode presently contemplated byus of carrying out our invention:

Fig. l is a side elevation of a circuit breaker pursuant to the presentinvention, a portion of the housing thereof being removed for purposesof illustration and the breaker being shown in the circuit open orinterrupting condition thereof;

Fig. 2 is a view similar to Fig. 1 and illustrates an intermediateposition through which the breaker mechanism passes during the closingoperation of the breaker;

Fig. 3 is a view similar to Fig. l and illustrates the closed or circuitmaking condition of the circuit breaker;

Fig. 4 is a fragmentary sectional view, on an enlarged scale taken onthe line 4-4 of Fig. 1;

Fig. 5 is an enlarged fragmentary sectional view taken on the line 55 ofFig. 3;

Fig. 6 is an enlarged view of the obstructing element in the circuitbreaker; and

Fig. 7 is a fragmentary sectional view taken on the line 7-7 of Fig. 5.

Referring now to the drawings in detail, there is illustrated a circuitbreaker 10 which is of the general type illustrated and described inPatent No. 2,647,186 to T. M. Cole, dated July 28, 1953, and in PatentNo. 2,642,- 509, dated June 16, 1953 to T. M. Cole and P. M.Christensen, both of which are assigned to the assignee hereof. As hereshown, the automatic circuit breaker 10 is provided with the body part12 of a two part insulated casing or housing, the cover thereof beingindicated at 14 in Figs. 4 and 5. The circuit breaker mechanism 16provided in said body part, as here shown, comprises the movable contactarm or switch member 18, mounted for pivotal movement, as hereinafterdescribed in detail. Said contact arm is provided with the movablecontact 20, at one end thereof, for engagement with and disengagementfrom a companion stationary contact 22 provided on a solderless terminalconnector 24. At its other end, the movable arm 18 is provided with apivotally mounted actuator 26 which is in operative engagement with thehandle or manual operating member 28 by means of a link 30 which forms atoggle with said handle. The movable contact arm 18 is also providedwith a current responsive or overload device, here shown as a bimetallicelement or latch 32, the free end 44 of which is in latched engagementwith the actuator 26 in the circuit making or closed condition of themechanism, as illustrated in Fig. 3. As here shown, the latch isconnected to the stab element 34, which constitutes the other terminalof the circuit breaker, by means of a flexible conductor 36. Also, ashere shown, the circuit breaker mechanism 16 is provided withelectro-magnetic means for effecting the disengagement thereof, saidmeans comprising an electromagnetic member 38 which is secured at oneend thereof to the latch and to the movable contact member and whichconstitutes a rigid armature. A spring 42 is interposed between thehandle 28 and the movable member 18, as illustrated in Figs. 1, 2 and 3.

The operation of the circuit breaker is described in detail in theabove-mentioned patents. However, it will be understood that thebimetallic element 32 operates to latch the manually operable actuator26 and to unlatch said actuator from the movable contact member 18, theunlatching taking place upon deflection of the bimetallic element 32causing the disengagement of the free end 44 thereof from the bottompart 46 of the actuator 26 upon the occurrence of an overload, or underother abnormal predetermined current conditions in the circuitcontrolled by the circuit breaker. When the bimetallic element 32 isdeflected from engagement with the actuator 26, spring 42 is effectiveto move the contact member 18 to its open position wherein the contact20 is disengaged from the companion stationary contact 22.

As here shown, the pivot for the movable contact member 18 isconstituted by a helically coiled spring member 48, the opposite ends ofwhich are mounted in bearing recesses provided in the casing parts 12and 14. Said recesses 50 are beveled in a downward direction, as at 52,and in a lateral direction, as at 54, so as to facilitate the bowing ofthe spring pivot 48 in said directions. Such spring pivot serves thepurpose of resiliently pressing the contacts together and to compensatefor contact wear and other variables, as disclosed in Patent 2,681,396issued June 15, 1954, to Cole and Christensen.

Pursuant to the present invention, provision is made for a temporaryobstruction to the closing of the con tacts in order to prevent theabnormally slOW operation of the handle 28 from resulting (asheretofore) in an abnormally slow closing engagement of the contacts andtherefore permitted the possible arcing of current across the gapbetween the contacts which served to heat the contacts and possiblyresulted in the sticking thereof upon engagement thereof. Morespecifically, provision is made for a snap or anti-tease lever orobstructing member 56 which, as here shown, is generally of U- shapeformation.

-At its bight, the lever 56 is provided with a slot 58 which extendsinto the arms 60 and 62 thereof. The member 56 is mounted on the movablecontact arm 18 by the engagement of a marginal edge projection 63 of thelatter in the slot 58. The main sring 42 of the circuit breaker servesto releasably position the member 56 during the closing operation of thebreaker. More specifically, a spring seat is defined in the member 56 bythe recessed portion 64 defined in the arm 60 and the crimped portion 66defined in the opposing arm 62, said portions cooperating to seat oneend of spring 42. It will be noted from Figs. 1, 2 and 3 that the lowerend of the main spring 42 seats in the recess 64 and on the crimpedportion 66, the spring 42 serving to releasably hold the member 56 inposition to prevent the closing movement of the contact member 18, as inFigs. 1 and 2, and as hereinafter described in detail. It will be notedalso that the body part 12 of the circuit breaker is provided with acamming surface 68 which terminates in a nose 70, which cooperates withsaid member 56, as hereinafter described to prevent temporarily theclosing of the breaker.

In the open or circuit interrupting condition of the circuit breaker,the free end 72 of the arm 68 of member 56 abuts the camming surface 68.Now, as the handle 28 is operated in a counter-clockwise direction,viewing Figs. 1 and 2, in order to close the circuit breaker 10, themovable contact arm 18 is rotated thereby in a clockwise direction foreffecting the engagement of the contacts and 22 so that the free end 72of the arm rides up the camming surface 68 and engages the nose 70, themember 56 being retained in position by the spring 42. Said engagementof the arm 60 and the nose 70 provides a temporary obstruction to theclosing of the circuit breaker, as will be apparent from Fig. 2, whichrepresents an intermediate position through which the handle passesduring the closing movement thereof. Continued movement of the handle insaid closing direction results in the conditioning of the toggle,constituted by the handle and the link 30, toward overcentered conditionthereof. Since the movable contact member 18 is temporarily preventedfrom the continued pivotal movement thereof toward the contact closingposition thereof, the closing force transmitted to the movable contactmember 18 through the link and the actuator 26 results in the bowing ofthe pivot spring 48 in the direction of the arrow 74 (Fig. 3) to effectlimited bodily movement of the movable contact member 18 in saiddirection, as in Fig. 5. Said bodily movement of the movable contactmember carries the free end 72 of the arm 60 past the nose 70 and out ofengagement therewith so as to free the movable contact member 18 tocomplete the closing engagement thereof by removing the temporaryobstruction which impeded said closing engagement thereof. By this time,the toggle has been conditioned in its overset condition. The engagementof the contacts is effected by the snap-locking action of the togglethat provides a fulcrum about which bowed spring 48 can pivotally drivemember 18 to provide a swift positive snap engagementof the contactswhich is independent of the control of the operator. It will beunderstood that continued opera ation of the handle 28 in the closingdirection after obstruction element 68 is arrested by casing part 68-70acts to bow and thereby stress spring 48, and that the closing of thecontacts results from partial return of the spring to itsunstressed-condition. A portion of the stress remains for providingcontact pressure.

While the described action of the spring pivot 48 in bodily shiftingmember 18 to the right might be sufficient in itself to release themember 56 from the nose 70, a positive action is preferred. Thispositive action is provided by the drive connection of the lug portion75 of the handle 28 with the upper end of the arm 62 of obstructingmember 56 to pivot the member 56 on its seat 63 on the movable contactmember 18 in a clockwise direction for effecting the positive removal ofthe obstruction to the closing movement of the contact arm 18. It willbe understood that the handle 28 may be provided with a suitable rigidpart, which is actuated thereby in the described manner for effectingsaid pivotal movement of the member 56, in place of the lug 75 thereofwhich, as here shown also serves to mount the upper end of the spring 42on the handle 28. In this connection, it will be understood that whilethe pivot spring 48 is desirable for assisting in the operation torelieve the temporary obstruction to the closing movement of the movablecontact arm 18, it is not essential to the present invention since saidaction may be provided entirely by the engagement of the member 56 bythe handle lug 75, or by an equivalent member operated by the handle.

As previously indicated, the pivot spring 48 is bowed and moves contactmember 18 in the direction of arrow 74 in Fig. 3, when the breaker isclosed. In said condition, the pivot spring 48 exerts a greater forcethan the tensioned main spring 42 and thus provides a desired contactpressure by overcoming the opening action of the main spring. However,When the bimetal latch 32 re leases the actuator 26, the pivot springreturns to its relaxed condition and bodily moves the contact member 18in a direction opposite the arrow 74. Consequently, if snap lever 56 wasrigid with the contact arm 18, said snap lever might engage the shoulderor nose 70 and slow down the opening of the breaker. In some cases thebreaker might not open at all, or might open only partially since thespring 42 might not be strong enough to overcome the fracional forcesresulting from the engagement of arm 60 of member 56 with the part 70 ofthe casing half 12 under the action of the pivot spring 48. In order toeliminate any such possibilities the slot 58 defined in the member 56 ismade long enough to allow a limited movement of said member to easilybypass the shoulder 70 on the casing when the breaker is being opened.More specifically, the member 56 pivots in a counter-clockwisedirection, viewing Fig. 3, on the marginal edge projection 76 of thecontact member 18. Consequently, it will be readily apparent that saidpivotal movement of the mem: ber 56 prevents the contact arm from beingheld against opening movement thereof.

As stated in the previously listed objects of the present invention,provision is made for a positive opening operation of the circuitbreaker mechanism on manual actua-, tion to open the breaker, which isespecially desirable in case the contacts should stick or weld to eachother. This feature also provides added protection in case the mainspring 42 should break or be. defective. In addition, in the automaticopening of the breaker there is an extra sharp blow to open thecontacts, which is an advantage in case the contacts should stick orhave a light or superficial weld to each other, and also to assist inthe accelerated opening of the breaker contacts upon automatic operationas well as upon manual operation of the handle. All of these highlydesirable results are achieved by the fact that the arm 62 of the member56 is elongated so that it is positioned in the path of movement of thehandle lug 77 in which the link 30 is pivotally mounted. In thisconnection it will be understood that upon manual operation of thehandle 28 from its closed position in Fig. 3 to its open position inFig. l, as well as upon automatic operation or opening of the breakerwherein the handle is moved from its closed to its open position by theexpansion of the main spring 42, said lug 77 strikes an extra sharpblow, under the expansion of said spring, to the arm 62. Consequently,if for any reason, there is resistance to the opening of the contacts,as for example when said contacts are superficially welded to eachother, or if on manual operation the spring 42 is ineffective, theeffect or force of said blow is transmitted to the movable contactmember 18 to assist or accelerzne the opening movement of the latter.

As previously indicated the bowed pivot spring 48 exerts a greater forcethan the tensioned main spring. Consequently, in the event that thehandle 28 should be physically retained in position substantially as inFig. 2, when the member 56 disengages the cam shoulder 7% on closingoperation of the breaker, the pivot spring will be effective to bodilymove the contact member 18 to snapengage the contacts and, therefore, toprovide a breaker which is handle free during the closing thereof. Thebreaker is also handle free upon automatic operation thereof. In thisconnection it will be understood that if the handle 28 is held in itsclosed-circuit position, as illustrated in Fig. 3, and if an abnormalcurrent condition such as an overload occurs, the bimetallic latch 32 isautomatically deflected so as to disengage and release the actuator 26.Consequently, the present invention provides an automatic circuitbreaker which is handle free both on closing and on automatic trippingthereof.

In addition, the combined operation of the toggle and the bowed pivotspring 48 when the member 56 is disengaged from the cam surface portion70 provides a quick-make action. The operation of the handle 28 instriking the member 56 upon automatic opening assists the spring 42, toprovide a quick-break action.

The subject matter of the present application relating to the provisionof means to prevent the sticking or fusing of the contacts is also thesubject matter of the applications of Alexander R. Norden, Serial No.397,527 and Serial No. 397,673, and the application of Thomas M. Coleand Paul M. Christensen, Serial No. 397,551 all filed concomitantlyherewith and all assigned to the assignee hereof. While we have shownand described the preferred embodiment of our invention, it will beunderstood that various changes may be made in the present inventionwithout departing from the underlying idea or principles of theinvention within the scope of the appended claims.

Having thus described our invention,- what we claim and desire to secureby Letters Patent, is:

l. A circuit breaker comprising a housi g, a stationary contact, amovable switch member provided with a contact for engagement with anddisengagement from said stationary contact, a manual operating memberfor effecting operation of said movable member to open and close saidbreaker, means conditioned by the closing operation of said operatingmember to provide a snapaction engagement of said contacts, a part insaid housing, and said movable switch member being provided with meansoperable during the closing operation of said operating member andadapted to cooperate with said part to obstruct the engagement of saidcontacts substantially until the conditioning of said snap-action means,whereby to effect the closing of said contacts by said snap-actionmeans, said obstructing means being actuated by said operating member torelieve the obstruction thereof, said part being stationary and adaptedto be releasably engaged by said obstructing means to preventtemporarily the engagement of said contacts, said obstructing meansbeing disengaged from said stationary part by said manual operatingmember, and said obstructing means having a portion actuated by saidmanual 6 operating member during the opening of the breaker whereby saidobstructing means clears said stationary part during said opening of thebreaker.

2. A circuit breaker comprising a housing, a stationary contact, amovable switch member provided with a contact for engagement with anddisengagement from said stationary contact, a manual operating memberfor effecting operation of said movable member to open and close saidbreaker, means conditioned by the closing operation of said operatingmember to provide a snapaction engagement of said contacts, a cammingsurface in said housing, and a member pivotally mounted on said switchmember for engagement with said camming surface during closing of thebreaker to prevent temporarily the engagement of said contacts, saidmounted member being pivoted by said manual operating member todisengage said camming surface substantially at the conditioning of saidsnap-action means whereby to effect the closing of said contacts by saidsnap-action means.

3. A circuit breaker comprising a housing, a stationary contact, amovable switch member provided with a contact for engagement with anddisengagement from said stationary contact, a manual operating memberfor effecting operation of said movable member to open and close saidbreaker, means conditioned by the closing operation of said operatingmember to provide a snapaction engagement of said contacts, a cammingsurface in said housing, and a member pivotally mounted on said switchmember for engagement with said camming surface during closing of thebreaker to prevent temporarily the engagement of said contacts, saidmounted member being pivoted by said manual operating member todisengage said camming surface substantially at the conditioning of saidsnap-action means whereby to effect c the closing of said contacts bysaid snap-action means,

said camming surface extending into the path of movement of said mountedmember during the opening of the breaker, and said manual operatingmember having provision to pivot said mounted member during the openingof the breaker to clear said camming surface.

4. A circuit breaker comprising a housing, a stationary contact, amovable contact member engageable and disengageable therewith, a breakerhandle, toggle means operated by said handle for effecting engagement ofsaid contact and said contact member, a camming surface in said housing,a member pivotally mounted on said contact member and engageable withsaid camming surface to prevent the closing of said breaker, a flexiblemounting for said movable contact member to effect bodily movement ofsaid movable contact member substantially at the oversetting of saidtoggle means, whereby to disengage said preventing member from saidcamming surface to provide for snap engagement of said contact andcontact member, and means for effecting pivotal movement of saidpreventing member during the opening of said breaker to clear saidcamming surface.

5. A circuit breaker comprising a housing, a stationary contact, amovable contact member engageable and discngageable therewith, a breakerhandle toggle means operated by said handle for effecting engagement ofsaid contact and said contact member, a camming surface in said housing,a member pivotally mounted on said contact member and engageable withsaid camming surface to prevent the closing of said breaker, a flexiblemounting for said movable contact member to effect bodily movement ofsaid movable contact member substantially at the oversetting of saidtoggle means, whereby to disengage said preventing member from saidcamming surface to provide for snap engagement of said contact andcontact member, and means for effecting pivotal movement of saidpreventing member during the opening of said breaker to clear saidcamming surface, said last mentioned means being a portion of saidpreventing member which is actnated by said handle during the openingmovement of said handle.

6. In an automatic circuit breaker having a housing, a

' stationary contact, a movable contact member for engagement anddisengagement therewith, an actuating member carried by said movablecontact member, a current responsive device for operatively connectingsaid actuating member releasably to said movable contact member foroperating the latter except when said current responsive device isdisconnected from said actuating member upon overload, a handle foreffecting manual operation of said actuator, means interconnectedbetween said handle and said actuator for effecting asnap-lockingengagement of said contact and contact member and springmeans operable to open said breaker to move said handle to an offposition thereof, and to automatically reset said breaker afterautomatic operation thereof; the combination of means in said housingand means releasably positioned by said spring means and adapted tocooperate with said means in said housing to prevent temporarily theengagement of said contact and contact member substantially until theconditioning of said interconnecting means to snap lock engage saidcontact and contact member into engagement, said preventing means beingmounted on said movable contact member and being formed to constitute aseat for said spring means.

7. In an automatic circuit breaker having a housing, a stationarycontact, a movable contact member for engagement and disengagementtherewith, an actuating member carried by said movable contact member, acurrent responsive device for operatively connecting said actuatingmember releasably to said movable contact member for operating thelatter except when said current responsive device is disconnected fromsaid actuating member upon overload, a handle for effecting manualoperation of said actuator, a connection between said handle and saidactuator for efiecting a snap-engagement of said contact and contactmember and spring means operable to open said breaker to move saidhandle to an ofi position thereof, and to automatically reset saidbreaker after automatic operation thereof; the combination of means insaid housing and means releasably positioned by said spring means andadapted to cooperate with said means in said housing to preventtemporarily the engagement of said contact and contact membersubstantially until the conditioning of said connection to snap engagesaid contact and contact member, said preventing means being pivotallymounted on said movable contact member and having a portion operatedupon by said handle to pivot said preventing means from contactengagement preventing disposition thereof.

8. In a automatic circuit breaker having a housing, a stationarycontact, a movable contact member provided with a contact for engagementwith and disengagement from said stationary contact, manually operablemeans including a manual operating member operatively connected to saidmovable contact member for effecting manual operation of said movablecontact member to open and close said contacts and spring means foreffecting separation of said contacts upon operation of said manualoperating member to open the breaker, that improvement which comprisesmeans to positively move said movable contact member to disengage saidcontacts upon manual operation of said manual operating member to openthe breaker, said last mentioned means comprising a part on said movablecontact member extending into the path of movement of said manualoperating member and acted upon by the latter during the openingmovement thereof, said circuit breaker having means conditioned duringthe closing operation of said manual operating member to provide asnap-engagement of said contacts, a cooperating portion in said housing,and said part on said movable contact member being adapted to cooperatewith said portion to prevent temporarily the closing of said breakeruntil the conditioning of said snapengagement means.

9. In an automatic circuit breaker having a housing,

astationary contact, a movable contact member provided with a contactfor engagement-with and disengagement from said stationary contact,manually operable means including a manual operation member operativelyconnected to said movable contact member for effecting manual operationof said movable contact member to open and close said contacts andspring means for effecting separation of said contacts upon automaticopening of said breaker, that improvement which comprises the provisionof means operable upon automatic opening of said breaker to strike saidmovable contact member for disengaging the contacts, said spring meansbeing operable upon said automatic opening of the breaker to move saidmanual operating member from a circuit making to a circuit breakingdisposition thereof, and said movable contact member having a partextending into said path of movement of said manual operating memberwhereby said manual operating member is effective to strike said movablecontact member to disengage said contacts, said circuit breaker havingmeans conditioned during the closing operation of said manual operatingmember to provide a snap-engagement of said contacts, a cooperatingportion in said housing and said part on said movable contact memberbeing adapted to cooperate with said portion to prevent temporarily theclosing of said breaker until the conditioning of said snap-engagementmeans.

10. In an automatic circuit breaker, relatively movable contact membersprovided with companion contacts, respectively, mechanism includingcontrol means for effecting automatic disengagement of said contactsupon the occurrence of predetermined current conditions, a handle formanually operating said mechanism to close and open the breaker, andmeans operable by said handle during breaker-opening movement thereof toexert a force in a direction to separate said contacts in the event thatnormal separation of said contacts is resisted, means conditioned inresponse to the closing operation of said mechanism to provide asnap-engagement of said contacts, and means operable to provide atemporary 0bstruction to prevent the engagement of said contacts untilthe conditioning of said snap-engagement means, whereby to effect theclosing of said contacts by said snap-engagement.

11. An electric circuit breaker having a stationary contact, a movablecontact member engageable and disengageable therewith, mechanismoperable to engage said contacts, a breaker handle for operating saidmechanism, a stationary part provided in said breaker, a memberpivotally mounted on 'said contact member and engageable with said partto prevent the closing of said breaker, and a flexible mounting for saidmovable member to effect bodily movement of said movable contact memberwhen said contact member is close to but out of engagement with saidstationary contact, whereby to etfect the instantaneous engagement ofsaid contact member with said stationary contact by causing said mountedmember to shift out of engagement with said part.

12. An electric circuit breaker having relatively movable contactsengageable with and disengageable from each other for closing andopening the circuit, means automatically operable in response to loadconditions of the circuit to disengage said contacts, mechanism operableto engage :said contacts, a handle mounted for movement in oppositedirections, means to effect the operation of said mechanism by movementof said handle in one direction until said contacts are close to eachother but out of engagement, and means to prevent the engagement of saidcontacts while they are close to each other, whereby the handle cannotbe operated to teaseclose said contacts, said preventing meanscomprising a part pivotally mounted by said mechanism and a stationarypart disposed in the path of movement of said pivotally mounted part toengage said mounted part during operation of said mechanism to closesaid contacts, said parts interacting with :said mechanism to cause theinstantaneous complete and firm engagement of said contacts upon pivotalmovement of said pivotally mounted part to disengage said stationarypart upon continued movement of said handle after said parts areengaged, and said handle being movable in the opposite direction toeffeet the operation of said mechanism to disengage said contacts.

13. An electric circuit breaker as defined in claim 12, furthercharacterized in that the handle is mounted for pivotal movement and hasa sustained connection to the operating mechanism in all phases of theoperation thereof.

14. An electric circuit breaker having cooperable contacts, andoperating mechanism for said contacts including a movable contact memberoperable to open and close the contacts, an operating handle movablebetween extreme positions in which said contacts are, respectively, openand closed, a drive mechanism interconnecting said handle and saidmovable contact member for progressively operating :said movable contactmember toward its closed position as the handle is moved toward itsclosed position, means automatically operable in response to the loadcondition of the circuit to open the contacts, and ob struction meanscoacting with said mechanism and initially effective to arrest theadvance of the movable contact member during said closing motion of:said handle and said obstruction means being thereafter released toallow closing of the contacts, said operating mechanism including'yieldable spring means allowing said handle to advance despite arrestof said movable contact member and said spring means causing saidsnap-closing of the contacts after release of the movable contactmember, said obstruction means including a fixed part in the circuitbreaker and an obstructing element movable on said movable contactmember and initially cooperable with said fixed part to prevent saidmovable contact member from moving in the contact-closing direction, anda drive connection between said operating handle and said obstructingelement effective to remove said obstructing element from cooperationwith said fixed part, thereby to release said movable contact member forsnap closing under the influence of said yieldable spring means.

15. A circuit breaker in accordance with claim 14, wherein said handlehas a further drive connection to said obstructing element effectiveduring the opening stroke of said handle for providing positive drivefor said movable contact member in the contact opening direction.

16. An electric circuit breaker including an enclosing housing, a pairof cooperable contacts and operating mechanism for said contacts withinthe housing, and a handle pivoted in the housing for operating saidmechanism, said mechanism including a pivoted contact member, acurrent-responsive element and an actuator carried by said movablecontact member and arranged for latching engagement when said circuitbreaker is closed, toggle means connecting said handle and said actuatorand arranged to progressively close and lock the contacts when thehandle is moved from the open extreme to the closed extreme andeffective to open the contacts when the handle is reversely operatedbetween said extremes, said toggle acting before the full closing strokeof said handle is completed to condition said contacts. for closing,said operating mechanism including yieldable spring means allowing thehandle to complete its operating stroke in the closing direction, aV-shaped obstructing element rockably carried by said movable contactelement, said obstructing element having one arm cooperable with a fixedpart of said housing and effective to arrest the closing travel of themovable contact member and said V-shaped element having a second armextending close to said operating handle, said operating handle havingtwo spaced apart portions adapted to drive said second arm back andforth when said handle is operated in opposite directions. one of saidhandle por- 10 tions being effective during the closing operation ofsaid handle to drive said obstructing element to release said arrestedmovable contact member when conditioned for contact-closing, and theother of said handle portions being cooperable with said second arm ofsaid obstructing element when the handle is moved in the openingdirection to provide positive drive for said movable contact member inthe opening direction, and a contact opening compression spring confinedbetween said one handle portion and the arms of said V-shapedobstructing element and effective to bias said handle in the openingdirection and to bias said obstructing element against said movablecontact member in the direction for engagement with said fixed part ofthe housing.

17. An electric circuit breaker including an enclosing housingcontaining a pair of cooperable contacts, automatic current-responsivecircuit breaker releasing means, and operating mechanism including amovable member for moving one of said contacts to open and close thecircuit breaker, a handle operable between open and closed extremes foroperating said mechanism and said mechanism including a spring enablingadvance of the handle in the closing direction without concurrentcontact-closing advance of said movable member, a movable elementcooperable with said movable member and with said handle in both openingand closing strokes thereof, and a stationary part cooperable with saidmovable element during closing operation of the handle to arrest saidmovable member temporarily and said handle being thereafter effective torelease said movable member to allow snap-closing of said contacts, andsaid handle being cooperable with said movable member via said elementto provide contact-opening drive in the event of sticking of thecontacts when the handle is moved in the opening irection.

18. An electric circuit breaker including a pair of cooperable contacts,operating mechanism for closing and opening said contacts, including amovable member, automatic current responsive contact-opening means and amanual member operable between open and closed extremes for opening andclosing said contacts, said mechanism causing engagement of the contactsbefore the handle reaches its closed extreme and said mechanismincluding a spring enabling advance of said manual member to its closedextreme after initial engagement of the contacts, a two-armed elementcarried by said movable member, one of the arms of said element beingcooperable with a stationary part of the circuit breaker to arrestclosing advance of the movable member and said manual member thereafterhaving a drive connection to the second arm of said twoarmed element todiscontinue said cooperation of said one arm and said stationary partand thereby release said member for snap-closing of the contacts, saidmanual member having a contact-opening connection to said second arm andthereby to said movable member in the event of sticking of the contacts.

19. An electric circuit breaker having cooperable contacts, andoperating mechanism for said contacts including a movable contact memberoperable to open and close the contacts, an operating handle movablebetween open and closed extremes, a drive mechanism interconnecting saidhandle and said movable contact member for progressively operating saidmovable contact member toward its closed position as the handle is movedtoward its closed position, said mechanism being arranged to provideinitial engagement of the contacts before the handle has reached itsclosed extreme and said mechanism having spring means allowing furtheradvance of the handle to the closed extreme after engagement of thecontacts, means automatically operable in response to the load conditionof the circuit to open the contacts, the combination with the foregoingof obstruction means coacting with said movable contact member andinitially effective to arrest the advance of the movable contact memberduring the closing operation of said handle, said spring means beingincreasingly stressed during the arresting operation of said obstructionmeans, said spring means being effective to produce snap-closing of thecontacts upon release of said obstruction means and said handle havingdrive connection to said obstruction means both in the closing and inthe opening direction of operation of the handle and effective torelease the obstruction means for contact closing as aforesaid andfurther etfective during the opening stroke of the handle to providecontact-opening thrust.

20. A circuit breaker in accordance with claim 19 wherein saidobstruction means includes a movable element carried by said movablecontact member and a fixed part cooperable with said movable element forarresting advance of the movable contact-member, and a spring actingbetween said handle and said movable element for biasing the handle inthe contact-opening direction and for biasing the movable element in thedirection to cooperate with said fixed part during initial closingoperation of the circuit breaker.

21. A circuit breaker having cooperable contacts, and operatingmechanism for said contacts including a moving contact member operableto open and close the contacts, an operating handle movable betweenextreme positions in which said contacts are, respectively, open andclosed, a drive mechanism interconnecting said handle and said movablecontact member and operable between open and closed extremes, a springacting between said handle and said movable contact member for biasingboth of said members in their contact-opening directions and said drivemechanism including toggle means and spring means arranged to causeinitial engagement of the contacts when the handle is operated in theclosing direction but before reaching the closed extreme and said togglebeing thereafter efiective to overset and thereby lock the contactsclosed and to stress said spring means for building contact pressure,that improvement in combination with the foregoing of means causing snapclosing of the contacts and preventing sticking of the contacts, saidlast-named means including an element movable on said movable contactmember and having an arm cooperable with said handle, said movableelement being adapted to cooperate with a fixed portion of the circuitbreaker during closing operation of said handle and being therebyarranged to prevent ad vance of said movable contact member in thecontactsclosing direction until said drive mechanism has beensufiiciently operated to produce initial engagement of the contacts andsaid movable element being thereafter operable by said handle tointerrupt the cooperation thereof with said fixed portion thereby tocause snap closing of the contacts, the handle cooperating with saidmovable element during the opening stroke of the handle in the event ofcontacts sticking together for forceable drive of the movable contactmember by said movable element to promote contact separation.

22. A circuit breaker in accordance with claim 21 wherein said movableelement is provided with a seat receiving said spring and said springthereby biasing said movable element against said movable contact memberand biasing the movable element toward cooperation with said fixedcircuit breaker portion during closing operation of the handle.

References Cited in the file of this patent UNITED STATES PATENTS2,013,827 Jennings Sept. 10, 1935 2,070,305 Jennings Feb. 9, 19372,126,412 Rowe Aug. 9, 1938 2,158,369 Jackson May 16, 1939 2,214,695Jennings Sept. 10, 1940 2,306,235 Walle Dec. 22, 1942 2,310,854 Lindstomet a1. Feb. 9, 1943 2,320,355 Frank et al. June 1, 1943 2,332,496 BaxterOct. 26, 1943 2,343,264 Platz Mar. 7, 1944 2,357,151 Von Hoorn Aug. 29,1944 2,416,266 Landmeier Feb. 18, 1947 2,426,880 Jackson et al. Sept. 2,1947 2,660,643 Toth Nov. 24, 1953 2,666,114 Jackson Jan. 12, 19542,681,397 Schwartz et al. June 15, 1954 2,692,926 Cole Oct. 26, 19542,697,765 Little Dec. 21, 1954 2,700,713 Cole et al. Jan. 25, 1955FOREIGN PATENTS 468,174 Canada Sept. 19, 1950

